From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugene Istomin Subject: Re: soft lockups of tapdisk2 process - xen 4.4, kernel 3.12.17 Date: Thu, 17 Apr 2014 09:39:27 +0300 Message-ID: <5596347.O7neOH1j5g@evis> References: <3712937.BtoHIzAgQ3@evis> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3712937.BtoHIzAgQ3@evis> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: Xen Devel List-Id: xen-devel@lists.xenproject.org We compare 3.12/3.13/3.14 kernels (keyword - PREEMPT_NEED_RESCHED), 3.12 haven't any patches for related to PREEMPT_NEED_RESCHED: 3.12 - https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/?id=refs%2Ftags%2Fv3.12.17&qt=grep&q=PREEMPT_NEED_RESCHED 3.13 - https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/?id=refs%2Ftags%2Fv3.13.10&qt=grep&q=PREEMPT_NEED_RESCHED 3.14 - https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/?id=refs%2Ftags%2Fv3.14.1&qt=grep&q=kmemleak.c What do you think about commit ba1f14fbe70965ae0fb1655a5275a62723f65b77 (https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=ba1f14fbe70965ae0fb1655a5275a62723f65b77 )? May this problem related to interrupt handling? [ 6624.928058] Call Trace: [ 6624.928058] [] notify_remote_via_ipi+0x82/0xb0 .. --- Best regards, Eugene Istomin On Thursday, April 17, 2014 08:11:25 AM Eugene Istomin wrote: Hello, after updating from xen 4.3 to xen 4.4 we have strange soft lockups, here is log - https://gist.github.com/evis/10953677. We already disabled c-states in BIOS, kernel (processor.max_cstate=1 intel_idle.max_cstate=0), dom0 (xenpm set-max-cstate 1). An easy step to reproduce in our environment - run 2 VMs with DRBD-backed disk. What "blktap_run_deferred" in this trace mean and why dom0 needs to call "blktap_device_restart"? force_evtchn_callback+0xe/0x10 blktap_device_restart+0xdf/0xf0 [blktap2] blktap_run_deferred+0xd1/0xe0 [blktap2] blktap_ring_ioctl+0x3a5/0x4d0 [blktap2] Thanks. --- Best regards, Eugene Istomin